A MECHANISM FOR HYSTERESIS IN BLACK HOLE BINARY STATE TRANSITIONS
- JILA, University of Colorado and NIST, 440 UCB, Boulder, CO 80309-0440 (United States)
We suggest that the hysteretic cycle of black hole state transitions arises from two established properties of accretion disks: the increase in turbulent stress in disks threaded by a net magnetic field and the ability of thick (but not thin) disks to advect such a field radially. During quiescence, magnetic field loops are generated by the magnetorotational instability at the interface between the inner hot flow and outer thin disk. Vertical flux is advected into and accumulates stochastically within the inner flow, where it stimulates the turbulence so that α ∼ 1. The transition to a geometrically thin inner disk occurs when L ∼ α{sup 2} L {sub Edd} ∼ L {sub Edd}, and the first ''thin'' disk to form is itself moderately thick, strongly magnetized, and able to advect field inward. These properties favor episodic jet production. As the accretion rate declines magnetic flux escapes, α decreases to α ∼ 0.01-0.1, and a hot inner flow is not re-established until L << L {sub Edd}. We discuss possible observational consequences of our scenario.
- OSTI ID:
- 22363989
- Journal Information:
- Astrophysical Journal Letters, Vol. 782, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
Similar Records
THE DISK EVAPORATION MODEL FOR THE SPECTRAL FEATURES OF LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI
MAGNETIC FLUX PARADIGM FOR RADIO LOUDNESS OF ACTIVE GALACTIC NUCLEI